The result of the project was the validation of the values ​​of biochemical parameters in saliva compared to the values ​​measured in the blood. At the same time, biochemical parameters were compared in two groups of horses characterized by different types of load. The study thus extended the existing knowledge on the equivalent use of non-invasive sampling to biochemical indicators, which until now have been determined in animals almost exclusively from blood. Evaluation of physiological changes in the body in connection with exercise is necessary for optimally selected training and management of horses, as well as for evaluating the level of welfare of horses.